everything has already been said, it's warm, it's this, it's that, but what isn't stressed is how it fits - it fits large. I wear small in most patagonia garments, but in this I need an extra small. That is, if you want it close fitting, and by close fitting I don't mean tight, show off boobs kind of tight. By close fitting I mean you can still wear a top and a thin sweater, then this on top. It is cut rather generous. I use these as a mid layer under all my none too warm winter coats, and as a liner under my waterproof shell, so this needs to me close fitting (not tight), and not too large that it makes the outer layer uncomfortable. Oh yeah, the arms are very generous and that's coming from a person that inherited rather fatty arms.